How to activate an app (DirectX and C++) (Windows)

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This topic shows how to define the activation experience for a Windows Store app built for Windows using DirectX with C++.

Register the app activation event handler

First, register to handle the CoreApplicationView::Activated event, which is raised when your app is started and initialized by Windows 8.

Add this code to your implementation of the IFrameworkView::Initialize method of your view provider (named MyViewProvider in the example):

C++



using namespace concurrency;
using namespace Windows::ApplicationModel;
using namespace Windows::ApplicationModel::Activation;
using namespace Windows::ApplicationModel::Core;
using namespace Windows::UI::Core;
using namespace Windows::UI::ViewManagement;

MyViewProvider::MyViewProvider() :
    // class fields
    // ...
    bool m_visible;
    bool m_windowsClosed;
{

}

void MyViewProvider::Initialize(
    _In_ CoreApplicationView^ applicationView
    )
{

   // ...

    applicationView->Activated +=
        ref new TypedEventHandler<CoreApplicationView^, IActivatedEventArgs^>(this, &DirectXApp::OnActivated);

   // ...

}

Activate the CoreWindow instance for the app

When your app starts, you must obtain a reference to the CoreWindow for your app. CoreWindow contains the window event message dispatcher that your app uses ro process window events. Obtain this reference in your callback for the app activation event by calling CoreWindow::GetForCurrentThread. Once you have obtained this reference, do the following:

Create and attach an event handler for the main app window activation event, CoreWindow::Activated. This event is fired when the main app window gains or loses focus.
Activate the main app window by calling CoreWindow::Activate.

C++



void MyViewProvider::OnActivated(
    _In_ CoreApplicationView^ /* applicationView */,
    _In_ IActivatedEventArgs^ /* args */
    )
{
    CoreWindow::GetForCurrentThread()->Activated +=
        ref new TypedEventHandler<CoreWindow^, WindowActivatedEventArgs^>(this, &MyViewProvider::OnWindowActivationChanged);
    CoreWindow::GetForCurrentThread()->Activate();
}

Handle any changes to the main app window state

Now, implement a method to handle any changes in the state of main app window (CoreWindow). In the following sample, you handle:

CoreWindowActivationState::Deactivated—the CoreWindow has lost focus. Your app can move to background processing behaviors.
CoreWindowActivationState::CodeActivated and CoreWindowActivationState::PointerActivated—the CoreWindow has gained focus from either a call to CoreWindow::Activate or user pointer interaction, respectively. Your app can start or resume foreground processing behaviors.

The complete set of CoreWindow states are enumerated in CoreWindowActivationState.

C++



void MyViewProvider::OnWindowActivationChanged(
    _In_ Windows::UI::Core::CoreWindow^ /* sender */,
    _In_ Windows::UI::Core::WindowActivatedEventArgs^ args
    )
{
    if (args->WindowActivationState == CoreWindowActivationState::Deactivated)
    {
        // CoreWindow does not have focus
    }
    else if (args->WindowActivationState == CoreWindowActivationState::CodeActivated
        || args->WindowActivationState == CoreWindowActivationState::PointerActivated)
    {
        // CoreWindow has focus
    }
}

Start processing event message for the main app window

Your callbacks occur as event messages processed by the CoreDispatcher for the app's CoreWindow. This callback will not be invoked if you do not call CoreDispatcher::ProcessEvents from your app's main loop (implemented in the IFrameworkView::Run method of your view provider).


// m_visible and m_windowsClose are class-level bool variables on MyViewProvider.

// ...

void MyViewProvider::Run()
{
    // your app's main loop!
    while (!m_windowClosed) // the app window is NOT closed
    {
        if (m_visible) // and if the app window is visible
        {
            CoreWindow::GetForCurrentThread()->Dispatcher->ProcessEvents(
                                                           CoreProcessEventsOption::ProcessAllIfPresent
                                                           );
        }
        else 
        {
            CoreWindow::GetForCurrentThread()->Dispatcher->ProcessEvents(
                                                           CoreProcessEventsOption::ProcessOneAndAllPending
                                                           );
        }
    }
}

How to activate an app (DirectX and C++)

Register the app activation event handler

Activate the CoreWindow instance for the app

Handle any changes to the main app window state

Start processing event message for the main app window

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